Answer: 13.2 seconds.
Explanation: using equation of motion; S= ut +1/2at² where u = initial velocity=0
S= distance travelled
a = acceleration due gravity
t= time.
1 foot = 0.305m so,
S= 2860 feet =872.3m
S= ut+1/2 at²
872.3 = 0×t + 1/2×10 × t²
872.3 =0 + 5t²
T²= 872.3/5
T²= 174.46
Take the square root of T we then have;
t = 13.2 seconds to one decimal place.
Answer:
563712.04903 Pa
Explanation:
m = Mass of material = 3.3 kg
r = Radius of sphere = 1.25 m
v = Volume of balloon = 
M = Molar mass of helium = 
= Density of surrounding air = 
R = Gas constant = 8.314 J/mol K
T = Temperature = 345 K
Weight of balloon + Weight of helium = Weight of air displaced

Mass of helium is 6.4356 kg
Moles of helium

Ideal gas law

The absolute pressure of the Helium gas is 563712.04903 Pa
Answer:
(a) t = 0 s
(b) t = 0 s, 30 s, 55 s
(c) t = 40 s to t = 60 s
(d) t = 10 s to t = 15 s
(e) a = 6 m/s^2
Explanation:
(a) The car is at starting position at t = 0 s and v = 0 m/s.
(b) The velocity of car is zero when the time is t = 0 s, 30 s and 55 s.
(c) from t = 40 s to 60 s the car is moving in the negative direction.
(d) The fastest speed is 60m/s from t = 10 s to t = 15 s.
(e) The slope of the velocity time graph gives acceleration.
a = (60 - 0) / (10 - 0) = 6 m/s^2
<h2>
Answer: False</h2>
Explanation:
This sentence is the description of the mechanical energy.
In this sense, the mechanical energy of a body or a system is that which is obtained from the speed of its movement (kinetic energy) or its specific position (potential energy), in order to produce a mechanical work.
That is to say: The mechanical energy involves both the kinetic energy and the potential energy (which can be elastic or gravitational, for example).
In addition, it should be noted that mechanical energy is<u> conserved in conservative fields and is a scalar magnitude.</u>
Therefore:
<h2>The sum of potential and kinetic energies in the particles of a substance is called <u>Mechanical Energy</u></h2>